1. Technical Field
The present invention relates generally to hand-held and hand-operated abrasive devices; and, more particularly, to a hand tool including a multi-pack of replaceable abrasive block inserts each having a multi-pack of abrasive sheets of selected grit--e.g., one abrasive block insert might include a multi-pack of 100 grit abrasive sheets; another might include a multi-pack of 150 grit abrasive sheets; a third might include a multi-pack of 200 grit abrasive sheets; etc.--or other selectable abrasive characteristics so as to permit the user to: i) select a particular insert having abrasive sheets of a desired grit and/or shape: ii) insert the selected insert into operative engagement with the hand-held tool; and iii), dispose of expended abrasive sheets on the selected insert merely by peeling such expended sheets off of the multi-pack on that insert so as to expose the underlying, fresh, unused abrasive sheet of the same grit and/or shape and/or other abrasive characteristic. As used herein, the term "abrasive sheet" is used in a broad non-limiting sense and may include a wide range of conventional flexible abrasive sheets such, merely by way of example, as sandpaper, emery cloth, etc.
More specifically, the present invention provides a plurality of replaceable abrasive inserts each of which serves to support a multi-pack of abrasive sheets of selected like abrasive characteristics, which sheets are "edge-bonded" together with the bottommost sheet being adhesively bonded in face-to-face relation with a rigid abrasive block insert capable of being inserted into a hand-held tool and frictionally retained in place until such time as the user elects to eject the rigid abrasive block insert and replace it with another insert also including a multi-pack of abrasive sheets, but having a different abrasive characteristic--e.g., a different grit size, a different abrasive material, etc.--or with an insert having a different shape, yet including a conformably shaped multi-pack of abrasive sheets.
2. Background Art
Hobbyists, furniture finishers and other individuals engaged in highly detailed finishing and/or refinishing projects have long required a small hand-held tool having an instantly replenishable supply of small abrasive sheets with selectable desired abrasive characteristics in terms of grit size, abrasive material, shape, etc., Yet, which does not need to be dismantled each time that the abrasive sheet in use is expended. Indeed, the prior art is replete with patents disclosing various approaches to the problem--approaches which have met with varying degrees of success, but all of which are believed to inherently possess one or more practical disadvantages.
For example, Johnston U.S. Pat. No. 3,842,549 discloses a sandpaper holder block having a head portion capable of receiving and clamping in place any selected one of a plurality of anvil inserts each having a desired shape. A single sheet of sandpaper is clamped in place in the holder block in surrounding relationship to the selected anvil insert. However, when that sheet of sandpaper has been expended, it is necessary to dismantle the tool in order to replace the expended sheet with a new unused sheet.
Several prior art patents disclose various types of hand-held sanding tools capable of mechanically clamping in place a plurality of discrete sandpaper sheets wherein the uppermost sheet can simply be torn off or otherwise removed when its abrasive characteristics have been depleted. For example, May U.S. Pat. No. 932,879, issued almost 80 years ago, discloses a sandpaper plane in which a plurality of sandpaper sheets are clamped to a hand-held tool along their opposed longitudinal edges in such a manner that expended sheets can be removed one-by-one after use without dismantling the tool. A somewhat similar device is disclosed in Pritikin U.S. Pat. No. 2,840,959 wherein the plurality of sheets are clamped in place at their opposite ends with expended sheets being individually removeable to expose the underlying unused sheet merely by releasing the clamping pressure. In U.S. Pat. No. 2,415,367 issued to Pavlovic, a plurality of sandpaper sheets or strips are folded about an elongate tool body and retained in place by projecting pins formed in the tool body. Retz U.S. Pat. No. 1,841,208 suggests stapling a plurality of abrasive sheets to a flat wood base; while Ingram U.S. Pat. No. 2,585,655 provides a spring loaded pressure tray mounted on a tool handle, with the tray having a plurality of folded over edge tabs for mechanically retaining a multi-pack of sandpaper sheets in place.
A number of prior patents have suggested the use of multiple sheets of abrasive material which are adhesively bonded together in such a manner that expended sheets can be peeled away from underlying unused sheets. Thus, Dirkes U.S. Pat. No. 1,822,856 discloses an abrasive pad consisting of a plurality of abrasive impregnated rubber layers separated by paper or fabric sheets and vulcanized together. U.S. Pat. No. 1,896,253 issued to Smith, 2d, discloses a device similar to that in the aforesaid Retz U.S. Pat. No. 1,841,208 except that the multi-pack abrasive sheets include a plurality of aligned through edge perforations which are filled with adhesive so as to separably secure the sheets together and to the base member. In Larson U.S. Pat. No. 2,485,295 and Thompson U.S. Pat. No. 2,626,489, adhesive material is placed on the reverse or non-abrasive side of each sheet for adhesively, yet separably, bonding that sheet to the abrasive side of the underlying sheet.
In Feuerstein U.S. Pat. No. 2,018,611, the patentee suggests positioning a plurality of equidimensional sandpaper sheets, preferably of different grits, on opposite sides of a central rigid block; and, retaining the entire assembly as a unitary package by wrapping an adhesive strip or tape about the peripheral edges of the assembly.
Finally, Field U.S. Pat. No. 2,826,014 discloses an abrasive tool in which a single sheet of sandpaper is adhesively bonded to a conical head.
In general, however, the foregoing patents have failed to provide a simple, effective and economical hand tool in which the user can select any given insert having a work face of desired shape and bearing thereon multi-pack abrasive sheets whose abrasive work surfaces are exposed one-by-one and which are devoid of foreign substances which tend to denegrate the abrasive characteristics of the sheet, yet which do not have to be dismantled when a given abrasive sheet is expended. Thus, neither Johnston nor Field contemplate or suggest a tool which is capable of use with multi-packs of abrasive material. While May and Pritikin do contemplate usage of multiple sheets of abrasive material, they are employed in single purpose sanding blocks which are not capable of utilizing different shaped inserts; and, in Pritikin the device must be disassembled to remove expended sheets. Pavlovic requires a complex tool/pin arrangement to hold the sheets in place, while both Retz and Ingram disclose devices incorporating exposed metal retainers overlying the work faces of the sanding device. In Dirkes, Smith 2d, Larson and Thompson, the exposed abrasive surfaces of each abrasive sheet will be contaminated with adhesive material from the overlying sheet; while in Feuerstein, the peripheral adhesive tape used to maintain the unitary packaged assembly will inherently interfere with the sanding operation as more and more expended abrasive sheets are removed.